The dispensing of liquid adhesives quickly and reliably in the manufacture of electronic circuit board assemblies with surface-mounted components is a difficult task. Rotary positive displacement pumps, pneumatically actuated syringes and momentum transfer jetting valves used in conventional fluid dispensing systems have inherent deposition accuracy limitations. For example, the deposition rate of fluid dispensed from a fluid dispensing valve may be influenced by regions of air trapped within the adhesive in the valve's fluid feed chamber, which may result in weight inconsistencies of dispensed fluid. Indeed, both the volume and shape of the dispensed fluid can be affected by the presence of an air bubble and can create the need for inspection and rework, which can increase fluid consumption and boost operating costs. As a result, the fluid dispensing process may impact the capability and throughput of an automated electronics assembly line.
While suppliers in the fluid dispensing industry have been able to make steady incremental improvements in reducing the presence of air bubbles via valve priming stations, the presence of air bubbles in the viscous material still continues to occur. As mentioned above, this phenomenon can adversely impact operation of the fluid dispensing valves and the cost of fluid dispensing. In addition, a lack of process automation and system verification can result in undesirable operator influences, as well as inefficient priming and set-up routines.
It would thus be beneficial to provide an improved system and method for valve priming that overcomes the aforementioned drawbacks and provides a level of process automation and system verification to help ensure consistent priming quality of the fluid dispensing valve.